With the trend in advanced turbine engine design toward lighter weight and higher performance, more flexible rotordynamic systems have evolved. The increased rotor flexibility and resultant component design changes have resulted in rotordynamic systems which are more responsive to imbalance. For this reason improved damper systems are required to control vibrations resulting from levels of imbalance up to five times the presently designed for levels.
Conventional squeeze film dampers, which are designed to control nominal levels of imbalance excited vibrations, are not necessarily effective in controlling the high levels of imbalance associated with events such as foreign object damage and blade loss in gas turbine engines. This becomes even more of a problem with advanced rotor designs where continuous operation under levels of imbalance up to five times their present levels may be expected. In accordance with this invention a segmented porous damper is provided in which damper energy absorption is essentially viscous and, hence, nearly linear throughout the entire range of expected vibrations. Thus, this invention eliminates the amplitude dependence of the squeeze film damper and the combined frequency/amplitude dependence resulting from orifice flow mechanisms, and results in linear, viscous damping with no cross coupling or inertia effects.